Besides watching the (not available for preview) "Cavemen" premiere last night, as well as recent doses of "Carpoolers," "Everybody Hates Chris," "Aliens in America," "30 Rock," "The Office," "My Name Is Earl," "How I Met Your Mother," "Two and a Half Men," "Girlfriends" and the overall picture is, well, mixed. ...

That list should demonstrate that the sitcom is far from dead. It may be getting tweaked ("Arrested Development" appears to have been as influential as it is unsuccessful). Still, that something as mind-numbingly dreadful as "Cavemen" could get on the air is an argument that networks have faith in the sitcom form.

"Cavemen" actually took a pilot with some interesting edges -- cavemen as oppressed minority -- and retooled it into a dull, formless mess. (This is not the first time a pilot has been screwed up. "The Wedding Album," a not terrible-seeming show, was revamped into the unrecognizable, dismal "Wedding Bells.") "Carpoolers," which ABC has paired with "Cavemen," is not the next great sitcom but it at least offered a couple of laughs.

But there are alarm bells going off in other parts of sitcom land. "How I Met Your Mother," capable of great style and humor, was a big old lump of boredom on Monday. Well, except for Robin's hair in Guatemala. But after a decent season premiere, this week's show was uncertain -- and I'm really puzzled by the seeming shift in Robin toward an overly sexualized creature (the note about Ted's size in the season premiere, the Robin-attracted-to-Robin moment this week -- shades of Kira and "Deep Space Nine.")

Then there's "Everybody Hates Chris," a show that I like a lot but haven't watched as much as I should have. During my absence -- or possibly just over this summer -- Tyler James Williams, who plays Chris, has gotten taller and deeper of voice, and the show's not as cute because of it. I know, young actors get older and change. But when a show still calls upon its main character to run upstairs crying "Daddy!" it doesn't sound as amusing when his voice has deepend. In fact, playing opposite Chris Rock -- yes, Chris Rock, not Kid Rock -- Williams's voice was deeper than the real-life adult his TV character is supposed to grow up to be.

The show still has its virtues, notably Tichina Arnold and Terry Crews as Chris's parents, but even they are getting pigeonholed. This week's show indicated there are only so many ways you can do a Terry-is-cheap story.

Not so much bad news as iffy news is "Aliens in America," a show that's charming and warm about its characters, but isn't all that funny. I've seen two episodes of it and thought, well, it's nice, and Scott Patterson is almost channeling Joe Flaherty's performance on "Freaks and Geeks." But when I sit down to watch a comedy, especially when I'm in the middle of weary times, I want to laugh. And "Aliens" at best made me smile.

So what made me laugh? Well, tomorrow's "30 Rock," with Jerry Seinfeld as himself, is pretty funny. Don't miss any of the bits from NBC shows, real and fictional, that Seinfeld has been put in. And always listen to Alec Baldwin -- especially when he's listing his most recent program concepts for NBC. Pirates, yes! Unfortunately, next week's episode is not as funny. But I have higher hopes of this bouncing back than I do for "HIMYM." Although I hope for it, too.

"Two and a Half Men" knows exactly what it is -- often crude comedy of aggravation -- and its two shows this year have delivered more of the same. And I still laugh. I was encouraged by the season premieres of "The Office" and "My Name Is Earl," but I haven't seen this week's shows yet, to be sure that they can maintain momentum.

And, among the shows that don't get talked about as much as they should, there's "Girlfriends." I haven't checked in with it in some time, but I still found a sturdy comedy-drama that understands its characters and their follies very well. And it's not afraid to push things. When Joan (Tracee Ellis Ross) was arguing with her fiance Aaron (Richard T. Jones), the intensity was so high that you could almost feel a threat of violence underlying their words.

So where does all this leave us? Pretty much where we've always been with comedies -- some good, some bad, some vacillating between two extremes. No reason to kill the form, and plenty of reason to keep trying to make it better.